A potential pathogenic factor from Mycoplasma hominis is a TLR2-dependent, macrophage-activating, P50-related adhesin.

PROBLEM: Mycoplasma hominis has been implicated in many inflammatory conditions of the human urogenital tract in particular amniotic infections that lead to fetal and neonatal disease and pre-term labor. The mechanisms responsible are poorly defined. METHOD OF STUDY: Biochemical and immunological methods were used to extract, purify, and characterize an inflammatory component present in M. hominis. RESULTS: We isolated and purified to homogeneity a 40-kDa bioactive lipoprotein from M. hominis that was a potent TLR2-dependent, CD14-independent activator of the human THP-1 macrophage cell line. Homology searches of the N-terminal sequence revealed that 22 of the first 23 residues were identical to those seen for the phase-variable M. hominis p50 adhesin. The truncated P50t lipoprotein importantly retained its adhesive properties for human macrophages. CONCLUSION: The unique adhesin/macrophage activator may play a key role in M. hominis infections by triggering an inflammatory cytokine cascade.